Antioxidant Effect of a Polyphenol-Rich Murtilla (Ugni molinaeTurcz.) Extract and Its Effect on the Regulation of Metabolism in Refrigerated Boar Sperm

Abstract

The production of reactive oxygen species (ROS) in boar spermatozoa increases in refrigeration; this can have an impact on sperm quality and fertilization capacity. We evaluated the effect of polyphenol-rich aqueous extract of murtilla (Ugni molinae Turcz) on boar sperm stored at 17°C in order to reduce oxidative stress and improve sperm quality in the long term. Five experiments were performed: first, characterization of the polyphenol content from five genotypes of murtilla; second, determination of the genotype with the best antioxidant effect (MT-Ex); third, the antioxidant capacity on O2- and lipid peroxidation; fourth, the influence of MT-Ex on motility, calcium movement, cAMP, and metabolic parameters; and fifth, analysis of long-term refrigeration. The average phenolic content was 344 ppm; gallic acid, catechin, quercetin, myricetin, and kaempferol were detected. All extracts evaluated presented a concentration-dependent antioxidant effect. MT-Ex reduces intracellular O2-/peroxides but low lipid peroxidation. MT-Ex in nonstimulated ROS conditions reduces sperm motility, mitochondrial membrane potential, cAMP, and ATP, but the succinate dehydrogenase activity remained normal; also, we observed a reduction in calcium movement in in vitro sperm capacitation. The long-term analyses showed that MT-Ex improved sperm motility decay and reduced membrane damage and ROS at 168 h. Based on this study, we propose MT-Ex as a supplement in semen extenders.

Effect of Hesperetin Treatment on Blood Glucose Level, Spermatozoa Quality, and Spermatozoa Quantity in Alloxan-Induced Diabetic Mice

“…Flavonoids can affect the process of spermatozoa transport to increase motility (Jofré et al, 2019). Adenosine triphosphatase enzyme maintains internal homeostasis for sodium and potassium ions.…”

Freeze-thawing impairs the motility, plasma membrane integrity and mitochondria function of boar spermatozoa through generating excessive ROS

“…Uncontrolled (i.e. excessive) ROS generation can attack unsaturated fatty acids (UFAs) on the plasma membrane, alter mitochondrial membrane potential and induce protein sulfhydryl peroxidation, thereby altering sperm function and structure [ 13 – 15 ], which is regarded as an important cause of sperm damage during cryopreservation [ 16 , 17 ]. In addition, ROS could cause that the sperm be unable to fertilize the oocyte.…”

Proline Protects Boar Sperm against Oxidative Stress through Proline Dehydrogenase-Mediated Metabolism and the Amine Structure of Pyrrolidine

“…Meanwhile, the antioxidant defense system in sperm is very limited [ 13 , 14 , 15 ]. Therefore, sperm is prone to lipid peroxidation (LPO) [ 6 , 16 ] and DNA damage [ 16 , 17 ] under oxidative stress. Moreover, excessive ROS damages the membrane structure and causes irreversible loss of motility [ 18 , 19 , 20 ].…”